Okay, I set up my 29 gallon reef tank about 2 months ago. My first purchase as far as coral go was a hammer coral. Of course the coral took a few days to acclimate itself to my tank, but soon was just as beautiful*if not even more* as when I saw it in the store. Anyhow, I went on vacation for 2 weeks and when I returned, my tank wasn't doing so well. Water was high in salt and algae was everywhere. My coral looked like a complete loss. After day of cleaning and a water change my water is testing A-OK. The only thing is, the coral hasn't come far around from being ill.
I figured It was a goner and pretty much decided to take it as a loss, but now it's a lot livelier than when I came home, so I thought I was back on track.
Being under the impression that everything was normal, I purchased a pulsing xenia...the guy at the LFS dropped it and it shriveled up really fast and I blamed this for the coral not recuperating, it's been about 5 days since I bought the xenia and the hammer is still not back in full swing of things(not nearly..)
Does anyone have any ideas for me to make them more comfortable?
Another thing is that quite a few of my snails have died and my rocks have lost some color, obviously I am doing something wrong but my tests are coming back fine. What should I do?

If you go on vacation, you need to have someone check the tank daily. Top-off water needs to be added daily to prevent the salinity from rising to high as result of evaporation. This is likely the sole cause of the problems with the Hammer. Give it time, It should come back nicely. They are a fairly hardy coral.

You saying your levels are all "fine" is not sufficient. To provide you with an accurate interpretation of your problem, we need you to post specifics. Temp, PH, Ammonia, Nitrite, Nitrate, Phosphate, Calcium, Alkalinity, Specific Gravity (or salinity). If you dont have the test kits for all of these, buy them. They are a must. Magnesium is also necessary but is of little concern this early into the life of your tank.

As for your snails, I'd wager they're simply starving to death. You can check for predators like conus snails, and parasites like baby pyramid snails, but I'd put money on the lack of ample food source being the culprit.